The present invention relates to a toner for use in plateable toner processes and in particular electroless metal plating as well as a method for producing the toner.
Plateable toner technology (PTT) relates to a localized metallization of a surface and in particular a polymeric surface by, e.g., xerographic or laser printing of a pattern followed by plating the pattern to the desired conductivity. See for example, Sorensen et al U.S. Pat. No. 4,504,529 which is incorporated herein by reference.
PTT employs the use of a "plateable" toner which has been formed by a single stage, spray drying process in which the particles have been imparted with the desired sensitizing and catalytic/activating properties. Suitable toners are discussed, for example, in Sorensen et al U.S. Pat. Nos. 4,495,216, Sorensen et al U.S. Pat. No. 4,518,738, and European Patent 0087135 to Sorensen et al, which patents are also incorporated by reference.
Despite the effectiveness of these toners in PTT processes, they also suffers from certain drawbacks. For example, it is desirable that the sensitizing compound be a tin salt. However, because these tin salts are heat sensitive, a spray drying process is employed in making these toners.
Furthermore, the use of spray drying in the production of toners produces a substantially spherical particle as compared to the generally "jagged" or irregular shape of toners produced by more conventional methods. These spherical shapes are not easily transferred in current electrophotographic equipment, e.g., printers, which are in fact optimized for the more traditional "jagged" shapes, and thus are not preferred in such environments.
The use of spray drying also limited the number of polymers which may be employed. For example, although an organic solution of a polymer is capable of being employed in a spray drying process, the environmental problems associated with the use of such organic solutions makes such processes impractical and uneconomical. Thus, the polymers which may be practically employed in spray drying processes are those which may be employed as a water-based latex.
Thus, the need clearly exists for a toner which is capable of overcoming these limitations of existing toners.